Overcoming Decomposition with Order-Reversed Quenching Obtained by Flash Melting

We report on an order-reversed quenching phenomenon in manganese nitrides under flash melting, which prevents the thermodynamically favorable phase transformations from occurring at high temperatures by providing a narrow window of time. The Mn-N kept un-decomposed at high temperatures generated by current up to 339 MA/m² within 60 ms. After flash melting, the Mn-N shows a significantly enhanced coercivity and a decreased crystalline size. The Mn-N samples decompose rapidly at temperatures above 1100 K with time. The order-reversed quenching technique is potentially useful in processing and preventing phase transformations of meta-stable materials at high temperatures.